44 SOILS 



recent investigations in soil bacteriology is ex- 

 tremely interesting and it may yield extremely 

 important results. 



CHEMICAL CHANGES IN THE SOIL 



The chemical changes that are constantly taking 

 place in every farm soil are no less numerous and 

 no less important than the changes resulting from 

 the work of bacteria. The elements of which the 

 soil is composed are always shifting and changing. 

 The compounds, which are merely combinations 

 of several elements, are continually dissolving 

 partnership and the elements join themselves to- 

 gether in new bonds, according to affinity. The 

 nitrogen released from a nitrate by the nitrogen- 

 wasting germs may be instantly seized by some 

 near-by hydrogen to make ammonia. The am- 

 monia may then be attacked by the nitrogen-saving 

 germs and made into nitrous acid; which, in turn, 

 may soon become a nitrate, or it may escape into 

 the air and be lost to the soil, until brought down 

 by rain. The phosphoric acid that the farmer 

 applies in superphosphate or bone meal is at once 

 seized by hungry elements and enters into several 

 partnerships. Some of it is readily soluble in 

 water and might leach away were there not some 

 lime or sodium handy to catch it. That part of it 

 which is not used by plants the first year or two 

 may get locked up so strongly in partnerships 

 with other elements that it becomes valueless to 

 plants. When a potash fertiliser, as ashes, is 

 applied to the soil, the plant food it contains would 

 mostly dissolve in the soil water and wash awav 

 were it not that it unites with some of the "bases ' 

 of the soil and becomes "fixed." In fact, the 



